High temperature vacuum seal

ABSTRACT

Gas distribution assemblies and process chamber comprising gas distribution assemblies are described. The gas distribution assembly includes a gas distribution plate, a lid and a primary O-ring. The primary O-ring is positioned between a purge channel of a first contact surface of the gas distribution plate and a second contact surface. Methods of sealing a process chamber using the disclosed gas distribution assemblies are described.

TECHNICAL FIELD

Embodiments of the present disclosure generally relate to apparatus andmethods for vacuum sealing a process chamber. In particular, embodimentsof the disclosure are directed to apparatus and methods to enable hightemperature vacuum sealing with decreased oxygen permeation.

BACKGROUND

During semiconductor manufacturing, process chambers often require hightemperature vacuum seals, ultra-pure environments and low molecularoxygen content during processing. Process chamber components areconnected with an O-ring to prevent metal-metal contact and form a seal.The seal formed is mostly fluid-tight but can allow permeation of someatmospheric gases. The permeation of gases is temperature sensitive,with increased permeation at greater temperatures. Since processchambers are often operated at elevated temperature, gas permeation ofthe O-ring increases significantly.

In convention processing chambers, dual seals with sufficientdifferential pumping are often used with high temperature vacuumassemblies. Application of dual seals has limitations where spaceconstraints are present. Additionally, incorporating dual sealstypically has a longer lead time as well and increased cost for customO-rings. Therefore, there is a need in the art for apparatus and methodsfor sealing process chamber environments from ambient gaseous speciesmigration.

SUMMARY

One or more embodiments of the disclosure are directed to gasdistribution assemblies comprising a gas distribution plate, a lid and aprimary O-ring. The gas distribution plate has a front surface and aback surface defining a thickness. The gas distribution plate comprisesa plurality of apertures extending through the thickness of the gasdistribution plate. The gas distribution plate has a sealing region atan outer edge. The sealing region has a first contact surface and asecond contact surface and the first contact surface comprises a purgechannel formed therein. The lid has a front surface and a back surfacedefining a thickness. The front surface of the lid is positionedadjacent the back surface of the gas distribution plate. The lidcomprises a purge gas line inlet with an opening at the front surfaceand a purge gas line outlet with an opening at the front surface. Theinlet opening and outlet opening are aligned with the purge channel ofthe first contact surface. The primary O-ring is positioned between thepurge channel of the first contact surface and the second contactsurface.

Additional embodiments of the disclosure are directed to processchambers comprising a chamber body having sidewalls and bottom boundinga process volume. A substrate support is within the process volume andhas a support surface. A gas distribution assembly comprising a gasdistribution plate, a lid and a primary O-ring bounds the processvolume. The gas distribution plate has a front surface facing thesupport surface of the substrate support and a back surface defining athickness. The gas distribution plate comprises a plurality of aperturesextending through the thickness of the gas distribution plate. The gasdistribution plate has a sealing region at an outer edge and the sealingregion has a first contact surface and a second contact surface. Thefirst contact surface comprises a purge channel formed therein. The lidhas a front surface and a back surface defining a thickness. The frontsurface of the lid is positioned adjacent the back surface of the gasdistribution plate. The lid comprises a purge gas line inlet with anopening at the front surface and a purge gas line outlet with an openingat the front surface. The inlet opening and outlet opening are alignedwith the purge channel of the first contact surface and the primaryO-ring positioned between the purge channel of the first contact surfaceand the second contact surface.

Further embodiments of the disclosure are directed to methods of sealinga process chamber. A pressure in a purge gas line is measured downstreamof a purge gas line outlet aligned with a purge channel in a gasdistribution assembly comprising a gas distribution plate and a lidseparated by a primary O-ring. The purge gas line is in fluidcommunication with a purge channel and a purge gas line inlet. Each ofthe purge gas line inlet and purge gas line outlet are aligned with thepurge channel. A flow of inert gas is provided into the purge channel sothat there is substantially no pressure differential between the gasdistribution plate and the purge channel.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above recited features of the presentdisclosure can be understood in detail, a more particular description ofthe disclosure, briefly summarized above, may be had by reference toembodiments, some of which are illustrated in the appended drawings. Itis to be noted, however, that the appended drawings illustrate onlytypical embodiments of this disclosure and are therefore not to beconsidered limiting of its scope, for the disclosure may admit to otherequally effective embodiments.

FIG. 1 shows a cross-sectional isometric view of a processing chamber inaccordance with one or more embodiment of the disclosure;

FIG. 2 shows a cross-sectional view of a processing chamber inaccordance with one or more embodiment of the disclosure;

FIG. 3 is an exploded cross-sectional view of a processing station inaccordance with one or more embodiment of the disclosure;

FIG. 4 is a schematic representation of a processing platform inaccordance with one or more embodiment of the disclosure;

FIG. 5 is a cross-sectional schematic view of a processing chamberaccording to one or more embodiment of the disclosure;

FIG. 6 is a partial cross-sectional schematic view of a region similarto region VI of FIG. 5;

FIG. 7 is a partial cross-sectional exploded schematic view of a gasdistribution assembly within a region similar to that of FIG. 6; and

FIG. 8 is a partial cross-sectional schematic view of a region similarto region VIII of FIG. 5.

DETAILED DESCRIPTION

Before describing several exemplary embodiments of the disclosure, it isto be understood that the disclosure is not limited to the details ofconstruction or process steps set forth in the following description.The disclosure is capable of other embodiments and of being practiced orbeing carried out in various ways.

As used in this specification and the appended claims, the term“substrate” refers to a surface, or portion of a surface, upon which aprocess acts. It will also be understood by those skilled in the artthat reference to a substrate can also refer to only a portion of thesubstrate, unless the context clearly indicates otherwise. Additionally,reference to depositing on a substrate can mean both a bare substrateand a substrate with one or more films or features deposited or formedthereon

A “substrate” as used herein, refers to any substrate or materialsurface formed on a substrate upon which film processing is performedduring a fabrication process. For example, a substrate surface on whichprocessing can be performed include materials such as silicon, siliconoxide, strained silicon, silicon on insulator (SOI), carbon dopedsilicon oxides, amorphous silicon, doped silicon, germanium, galliumarsenide, glass, sapphire, and any other materials such as metals, metalnitrides, metal alloys, and other conductive materials, depending on theapplication. Substrates include, without limitation, semiconductorwafers. Substrates may be exposed to a pretreatment process to polish,etch, reduce, oxidize, hydroxylate, anneal, UV cure, e-beam cure and/orbake the substrate surface. In addition to film processing directly onthe surface of the substrate itself, in the present disclosure, any ofthe film processing steps disclosed may also be performed on anunderlayer formed on the substrate as disclosed in more detail below,and the term “substrate surface” is intended to include such underlayeras the context indicates. Thus for example, where a film/layer orpartial film/layer has been deposited onto a substrate surface, theexposed surface of the newly deposited film/layer becomes the substratesurface.

As used in this specification and the appended claims, the terms“precursor”, “reactant”, “reactive gas” and the like are usedinterchangeably to refer to any gaseous species that can react with thesubstrate surface, or with a film formed on the substrate surface.

One or more embodiments of the disclosure advantageously providetechniques to enable high temperature vacuum sealing. Some embodimentsprovide apparatus and methods for efficient removal of gaseous speciesoutgassed from O-rings, minimizing or eliminating negative effects ofatmospheric molecular oxygen (O₂) in the processing environment.

Some embodiments of the disclosure are directed to gas distributionassemblies with a pump-purge channel along with single seal (O-ring). Insome embodiments, the channel is continuously purged by an inert gas(e.g., Ar, N₂) to maintain equal pressure in the chamber and thechannel. Stated differently, the pressure differential (ΔP) between thechannel and the process chamber is minimized. In some embodiments, thepressure different is substantially zero (ΔP=0). The zero pressuredifferential prevents inert or purge gas (e.g., Ar, N₂) flowing into thereaction space of the chamber.

In some embodiments, a pressure transducer is used to control thepressure in the purge channel relative to the pressure in the processchamber. In some embodiments, the gas distribution assembly includesmore than one purge gas channel, or the process chamber includes morethan one gas distribution assembly with purge gas channels. In someembodiments, each purge channel pressure is individually controlled withrespect to surrounding gas pressure. In some embodiments, purge gas(e.g., Ar, N₂) diffusion into the chamber or into a gas channel in theshowerhead is substantially zero since purge channel will becontinuously purged and pumped out. In some embodiments, a pulse-purgemechanism is used to remove or eliminate contamination due to O-ringdefects or trapped gas.

Some embodiments of the disclosure use less space to incorporate thepurge channel mechanism than conventional dual seal process chambers. Insome embodiments, the process chamber is isolated from atmospherewithout a dual seal arrangement as is understood by the skilled artisan.In some embodiments, high temperature induced O-ring outgassing ispurged out of the system without flowing into the process cavity. Insome embodiments, O-ring materials are not directly exposed to processchemistry. Some embodiments prevent O-ring defect migration and/orchemical bi-product flow into the chamber. Some embodiments provide gasdistribution assemblies with improved manufacturing lead times relativeto convention dual seal systems. In some embodiments, the oxygen (O₂)content in chamber is reduced.

The disclosure provides gas distribution assemblies for use with singlewafer or multi-wafer (also referred to a batch) process chambers. FIGS.1 and 2 illustrate a processing chamber 100 in accordance with one ormore embodiment of the disclosure. FIG. 1 shows the processing chamber100 illustrated as a cross-sectional isometric view in accordance withone or more embodiment of the disclosure. FIG. 2 shows a processingchamber 100 in cross-section according to one or more embodiment of thedisclosure. Accordingly, some embodiments of the disclosure are directedto processing chambers 100 that incorporate a substrate support 200 andtop plate 300.

The processing chamber 100 has a housing 102 with walls 104 and a bottom106. The housing 102 along with the top plate 300 define a processingvolume 109, also referred to as an interior volume.

The processing chamber 100 illustrated includes a plurality ofprocessing stations 110. The processing stations 110 are located in theinterior volume 109 of the housing 102 and are positioned in a circulararrangement around the rotational axis 211 of the substrate support 200.Each processing station 110 comprises a gas distribution plate 112 (alsoreferred to as a gas injector) having a front surface 114. In someembodiments, the front surfaces 114 of each of the gas injectors 112 aresubstantially coplanar. The processing stations 110 are defined as aregion in which processing can occur. For example, in some embodiments,a processing station 110 is defined as a region bounded by the supportsurface 231 of the heaters 230, as described below, and the frontsurface 114 of the gas injectors 112. In the illustrated embodiment, theheaters 230 act as substrate support surfaces and form part of thesubstrate support 200.

The processing stations 110 can be configured to perform any suitableprocess and provide any suitable process conditions. The type of gasdistribution plate 112 used will depend on, for example, the type ofprocess being performed and the type of showerhead or gas injector. Forexample, a processing station 110 configured to operate as an atomiclayer deposition apparatus may have a showerhead or vortex type gasinjector. Whereas, a processing station 110 configured to operate as aplasma station may have one or more electrode and/or grounded plateconfiguration to generate a plasma while allowing a plasma gas to flowtoward the wafer. The embodiment illustrated in FIG. 2 has a differenttype of processing station 110 on the left side (processing station 110a) of the drawing than on the right side (processing station 110 b) ofthe drawing. Suitable processing stations 110 include, but are notlimited to, thermal processing stations, microwave plasma,three-electrode CCP, ICP, parallel plate CCP, UV exposure, laserprocessing, pumping chambers, annealing stations and metrology stations.

FIG. 3 illustrates an exploded view of a gas distribution assembly 105for use in a processing station 110 or a process chamber in accordancewith one or more embodiment of the disclosure. The skilled artisan willrecognize that embodiment illustrated in FIG. 3 is a general schematicand omits details (e.g., gas channels). The gas distribution assembly105 illustrated comprises three main components: a gas distributionplate 112, a lid 180 and an optional spacer 330. The spacer 330 is alsoreferred to as a pump/purge spacer, insert or pump/purge insert. In someembodiments, the spacer 330 is connected to or in fluid communicationwith a vacuum (exhaust). In some embodiments, the spacer 330 isconnected to or in fluid communication with a purge gas source.

The openings 310 in the top plate 300 can be uniformly sized or havedifferent sizes. Different sized/shape gas injectors 112 can be usedwith a pump/purge spacer 330 that is suitably shaped to transition fromthe opening 310 to the gas distribution plate 112. For example, asillustrated, the pump/purge spacer 330 includes a top 331 and bottom 333with a sidewall 335. When inserted into the opening 310 in the top plate300, a ledge 334 is configured to be positioned in the opening 310.

The pump/purge spacer 330 includes an opening 339 in which a gasdistribution plate 112 can be inserted. The gas distribution plate 112illustrated has a flange 342 which can be in contact with the ledgeformed by the back surface 332 adjacent the top 331 of the pump/purgespacer 330. The diameter or width of the gas distribution plate 112 canbe any suitable size that can fit within the opening 339 of thepump/purge spacer 330. This allows gas injectors 112 of various types tobe used within the same opening 310 in the top plate 300.

FIG. 4 shows a processing platform 400 in accordance with one or moreembodiment of the disclosure. The embodiment shown in FIG. 4 is merelyrepresentative of one possible configuration and should not be taken aslimiting the scope of the disclosure. For example, in some embodiments,the processing platform 400 has a different numbers of one or more ofthe processing chambers 100, buffer stations 420 and/or robot 430configurations than the illustrated embodiment.

The exemplary processing platform 400 includes a central transferstation 410 which has a plurality of sides 411, 412, 413, 414. Thetransfer station 410 shown has a first side 411, a second side 412, athird side 413 and a fourth side 414. Although four sides are shown,those skilled in the art will understand that there can be any suitablenumber of sides to the transfer station 410 depending on, for example,the overall configuration of the processing platform 400. In someembodiments, there the transfer station 410 has three sides, four sides,five sides, six sides, seven sides or eight sides.

The transfer station 410 has a robot 430 positioned therein. The robot430 can be any suitable robot capable of moving a wafer duringprocessing. In some embodiments, the robot 430 has a first arm 431 and asecond arm 432. The first arm 431 and second arm 432 can be movedindependently of the other arm. The first arm 431 and second arm 432 canmove in the x-y plane and/or along the z-axis. In some embodiments, therobot 430 includes a third arm (not shown) or a fourth arm (not shown).Each of the arms can move independently of other arms.

The embodiment illustrated includes six processing chambers 100 with twoconnected to each of the second side 412, third side 413 and fourth side414 of the central transfer station 410. Each of the processing chambers100 can be configured to perform different processes.

The processing platform 400 can also include one or more buffer station420 connected to the first side 411 of the central transfer station 410.The buffer stations 420 can perform the same or different functions. Forexample, the buffer stations may hold a cassette of wafers which areprocessed and returned to the original cassette, or one of the bufferstations may hold unprocessed wafers which are moved to the other bufferstation after processing. In some embodiments, one or more of the bufferstations are configured to pre-treat, pre-heat or clean the wafersbefore and/or after processing.

The processing platform 400 may also include one or more slit valves 418between the central transfer station 410 and any of the processingchambers 100. The slit valves 418 can open and close to isolate theinterior volume within the processing chamber 100 from the environmentwithin the central transfer station 410. For example, if the processingchamber will generate plasma during processing, it may be helpful toclose the slit valve for that processing chamber to prevent stray plasmafrom damaging the robot in the transfer station.

The processing platform 400 can be connected to a factory interface 450to allow wafers or cassettes of wafers to be loaded into the processingplatform 400. A robot 455 within the factory interface 450 can be usedto move the wafers or cassettes into and out of the buffer stations. Thewafers or cassettes can be moved within the processing platform 400 bythe robot 430 in the central transfer station 410. In some embodiments,the factory interface 450 is a transfer station of another cluster tool(i.e., another multiple chamber processing platform).

A controller 495 may be provided and coupled to various components ofthe processing platform 400 to control the operation thereof. Thecontroller 495 can be a single controller that controls the entireprocessing platform 400, or multiple controllers that control individualportions of the processing platform 400. For example, the processingplatform 400 of some embodiments comprises separate controllers for oneor more of the individual processing chambers 100, central transferstation 410, factory interface 450 and/or robots 430.

In some embodiments, the processing chamber 100 further comprises acontroller 495 connected to the plurality of substantially coplanarsupport surfaces 231 configured to control one or more of the firsttemperature or the second temperature. In one or more embodiments, thecontroller 495 controls a movement speed of the substrate support 200(FIG. 2).

In some embodiments, the controller 495 includes a central processingunit (CPU) 496, a memory 497, and support circuits 498. The controller495 may control the processing platform 400 directly, or via computers(or controllers) associated with particular process chamber and/orsupport system components.

The controller 495 may be one of any form of general-purpose computerprocessor that can be used in an industrial setting for controllingvarious chambers and sub-processors. The memory 497 or computer readablemedium of the controller 495 may be one or more of readily availablememory such as random access memory (RAM), read only memory (ROM),floppy disk, hard disk, optical storage media (e.g., compact disc ordigital video disc), flash drive, or any other form of digital storage,local or remote. The memory 497 can retain an instruction set that isoperable by the processor (CPU 496) to control parameters and componentsof the processing platform 400.

The support circuits 498 are coupled to the CPU 496 for supporting theprocessor in a conventional manner. These circuits include cache, powersupplies, clock circuits, input/output circuitry and subsystems, and thelike. One or more processes may be stored in the memory 498 as softwareroutine that, when executed or invoked by the processor, causes theprocessor to control the operation of the processing platform 400 orindividual processing chambers in the manner described herein. Thesoftware routine may also be stored and/or executed by a second CPU (notshown) that is remotely located from the hardware being controlled bythe CPU 496.

Some or all of the processes and methods of the present disclosure mayalso be performed in hardware. As such, the process may be implementedin software and executed using a computer system, in hardware as, e.g.,an application specific integrated circuit or other type of hardwareimplementation, or as a combination of software and hardware. Thesoftware routine, when executed by the processor, transforms the generalpurpose computer into a specific purpose computer (controller) thatcontrols the chamber operation such that the processes are performed.

In some embodiments, the controller 495 has one or more configurationsto execute individual processes or sub-processes to perform the method.The controller 495 can be connected to and configured to operateintermediate components to perform the functions of the methods. Forexample, the controller 495 can be connected to and configured tocontrol one or more of gas valves, actuators, motors, slit valves,vacuum control or other components.

In one or more embodiments, the processing chamber 100 further comprisesat least one wafer on the support surface. In some embodiments, thefirst emissivity and the first temperature and/or the second emissivityand the second temperature provide a steady state temperature of thewafer in the first station and in the second station.

FIGS. 5 through 8 illustrate one or more embodiments of a gasdistribution assembly 105. FIG. 5 illustrates a cross-sectionalschematic view of a processing chamber 100 with the gas distributionassembly 105. FIG. 6 illustrates a schematic cross-sectional view of agas distribution assembly 105 similar to that of region VI in FIG. 5.FIG. 7 illustrates an exploded view of the gas distribution assembly 105of FIG. 6. FIG. 8 illustrates a schematic cross-sectional view of a gasdistribution assembly 105 similar to that of region VIII in FIG. 5.

In some embodiments, the gas distribution assembly 105 comprises a gasdistribution plate 112 with a lid 180. The gas distribution plate 105has a front surface 114 and a back surface 115 defining a thickness ofthe gas distribution plate 112. In the illustrated embodiment the outerperipheral regions of the gas distribution plate 112 have surfacefeatures and contact surfaces that are described below and are notconsidered part of the back surface 115. The back surface 115 is thesurface of the gas distribution plate 112 that another component cancontact and provide a fluid path for gases to pass through the thicknessof the gas distribution plate 112 through a plurality of apertures 133extending through the thickness.

In the illustrated embodiment, the gas distribution plate 112 comprisesa plurality of channels 130 formed in the back surface 115. Each of theplurality of channels 130 extends a distance toward the front surface114 to a channel bottom 131 and the apertures 133 are positioned withinthe channels 130 to extend from the channel bottom 131 to the frontsurface 114 of the gas distribution plate 112.

In the illustrated embodiment, the gas distribution plate 112 has asealing region 135 at an outer peripheral edge. The sealing region 135of some embodiments extends beyond the back surface 115 and is not partof the back surface 115. The sealing region 135 of some embodiments hasone or more contact surfaces configured to be positioned adjacent to orin contact with an adjacent component. In some embodiments, the sealingregion 135 has a first contact surface 136 and a second contact surface137.

In some embodiments, the first contact surface 136 comprises a purgechannel 140 formed therein. The purge channel 140 has a width W_(p)measured from a center of the gas distribution plate toward the outeredge of the gas distribution plate and a depth D_(p) measured from thecontact surface into the body of the gas distribution plate. The widthW_(p) of the purge channel 140 can be any suitable width. In someembodiments, the width W_(p) of the purge channel 140 is in the range ofabout 0.1 mm to about 50 mm, or in the range of about 0.5 mm to about 25mm, or in the range of about 1 mm to about 10 mm. In some embodiments,the depth Dp of the purge channel 140 is in the range of about 0.1 mm toabout 10 mm, or in the range of about 0.5 mm to about 5 mm.

The purge channel 140 extends around the periphery of the back surface115 of the gas distribution plate 112. The boundary of the back surface115 of some embodiments is the area of the gas distribution plate 112within the perimeter of the purge channel 140. In some embodiments, thewidth and/or depth of the purge channel 140 changes along the length ofthe channel so that the purge channel is wider in some areas and deeperin others. In some embodiments, the width and/or depth of the purgechannel remains substantially the same along the length (perimetermeasured at the mid width of the channel). As used in this manner, theterm “substantially the same” means that the width of the channel at anylocation is within ±10%, ±5%, ±2% or ±1% of the average width of thechannel.

The gas distribution assembly 105 includes a lid 180. The lid 180 has aback surface 181 and a front surface 182. The lid 180 is configured tohave the front surface 182 is be positioned adjacent the back surface115 of the gas distribution plate 112. In some embodiments, the lid 180directly contacts the gas distribution plate 112. In some embodiments,the lid 180 contacts the gas distribution plate through one or moreO-rings.

The lid 180 of some embodiments comprises a purge gas line 190 with oneor more opening 191 at the front surface 182 of the lid 180. In someembodiments, the opening 191 of the purge gas line 190 extends aroundthe periphery of the front surface 182 and separates the front surface182 from the contact surfaces outside the perimeter of the purge gasline opening 191. The purge gas line 190 has a purge gas line inlet 192(shown in FIG. 8) and a purge gas line outlet 193 (shown in FIGS. 6 and7). Each of the purge gas line inlet 192 and outlet 193 has an opening191 at the front surface 182. In some embodiments, the inlet 192 opening191 and outlet 193 opening 191 are aligned with the purge channel 140formed in the first contact surface 136 of the gas distribution plate112.

In some embodiments, a primary O-ring 150 is positioned between thepurge channel 140 of the first contact surface 136 and the secondcontact surface 137. In some embodiments, the primary O-ring 150 ispositioned in a primary O-ring recess 151 in the first contact surface136 of the gas distribution plate 112. The depth of the primary O-ringrecess 151 can be varied based on, for example, the particular O-ring150 being used or the shape of the lid. Any suitable material known tothe skilled artisan can be used for the primary O-ring 150.

In some embodiments, as shown in FIGS. 6 and 7, a secondary O-ring 155is positioned between the back surface 115 of the gas distribution plate112 and the front surface 182 of the lid 180. In some embodiments, asillustrated, the second O-ring 155 is positioned on an opposite side ofthe purge channel 190 from the primary O-ring 150. Stated differently,in some embodiments, the secondary O-ring 155 is positioned within theperiphery of the primary O-ring 150 or within the periphery of the purgechannel 190. The secondary O-ring 155 of some embodiments segregates thechannels of the segregation o-ring between channels of the gasdistribution plate.

The secondary O-ring 155 of some embodiments segregates adjacentchannels 130 formed in the back surface 115 of the gas distributionplate 112. In some embodiments, the secondary O-ring 155 is positionedwithin a recess 184 formed in one or more of the back surface 115 of thegas distribution plate 112 or the front surface 182 of the lid 180. Theillustrated embodiment shows the secondary O-ring 155 positioned withinrecesses 184 in the front surface 182 of the lid 180. The secondaryO-ring 155 of some embodiments is aligned with the outer edge 138 of theoutermost channel 130 a. The secondary O-ring 155 of some embodimentsseparates the gas flow path from the lid 180 through the gasdistribution plate 112 to the process chamber from the purge channel190.

In some embodiments, there is a secondary O-ring 155 positioned betweeneach of the channels 130 in the back surface 115 of the gas distributionplate 112. In some embodiments, the secondary O-ring 155 is aligned witha partition separating the adjacent channels. In some embodiments, thechannels 130 form one or more intertwined spiral paths and the recesses184 have a complementary shape and the second O-ring 155 extends alongthe recesses 184.

Some embodiments of the gas distribution plate 112 further comprises aspacer ring 330 between the gas distribution plate 112 and the opening310 in the top plate 300. The spacer ring 330 has an inside surface 337,an outside surface 338 and a back surface 332. The inside surface 337 ispositioned adjacent an outside surface 141 of the gas distribution plate112. As shown in FIG. 7, in some embodiments, the back surface 332 ofthe spacer ring 330 is positioned adjacent a third contact surface 143in the sealing region 135 of the gas distribution plate 112.

Referring to FIGS. 5 and 8, the gas distribution plate 112 of someembodiments further comprises a spacer ring 330 purge gas line 336extending through the gas distribution plate 112 from the back surfaceof sealing region 135 to the third contact surface 143. In someembodiments, the spacer ring purge gas line 336 comprises a spacer ringpurge gas line inlet 336 a with an opening 341 at the back surface ofthe sealing region 135 of the gas distribution plate 112 and a spacerring purge gas line outlet 336 b with an opening 341 at the back surfaceof the sealing region 135 of the gas distribution plate 112. In someembodiments, the inlet opening 341 and outlet opening 341 are alignedwith a spacer ring purge channel 371. In some embodiments, as shown inFIG. 8, the spacer ring purge channel 371 is formed in the third contactsurface 143 of the gas distribution plate 112. In some embodiments, asshown in FIG. 7, the spacer ring purge channel 371 is formed in the backsurface 332 of the spacer ring 330. In some embodiments, a spacer ringpurge channel O-ring 372 is in the spacer ring purge channel 371.

Some embodiments of the gas distribution assembly 105, as shown in FIGS.5 and 8, further comprise a pressure transducer 390 in communicationwith the purge gas line inlet 192. In some embodiments, the pressuretransducer 390 is in fluid communication with the purge gas line inlet192 so that a purge gas 391 flowing through line 392 can be controlledto maintain the pressure differential. In some embodiments, the pressuretransducer 390 controls the flow of purge gas into both the purge gasline inlet 192 and the spacer ring purge gas line inlet 336 a at thesame time. In some embodiments, there is a separate pressure transducerfor the spacer ring purge gas line 336 a than the purge gas line inlet192. In some embodiments, a pressure gauge 393 is in the purge gas lineupstream of the inlet 192. In some embodiments, there is a pressuregauge 393 position in the purge gas line outlet 193. In someembodiments, the pressure transducer 390 is in communication with one ormore of the purge gas line inlet 192 of the spacer ring purge gas lineinlet 336 a. In some embodiments, the pressure transducer 390 is incommunication with one or more of the purge gas line inlet 192 or thespacer ring purge gas line inlet 336 a. In some embodiments, a pressuregauge 393 is positioned in one or more of the purge gas line outlet 193or the spacer ring gas line outlet 336 b.

Some embodiments of the gas distribution assembly 105 include acontroller 495, as shown in FIG. 4. The controller 495 of someembodiments is configured to control the pressure transducer 390 basedon measurements from the pressure gauge 393 to provide a flow of inertgas into the purge gas line inlet 192 sufficient to maintainsubstantially no pressure differential between the gas distributionplate 112 and the purge channel 140. In some embodiments, the controller495 is configured to control the pressure transducer 390 based onmeasurements from the pressure gauge 393 to provide a flow of inert gasinto one or more of the purge gas line inlet 192 or spacer ring gas lineinlet 336 a sufficient to maintain substantially no pressuredifferential between the gas distribution plate 112 and the purgechannel 140 or between the gas distribution plate 112 and the spacerring purge channel 371.

One or more embodiments of the disclosure are directed to methods ofsealing a process chamber. The pressure in a purge gas line is measuredat any suitable position along the flow path of the purge gas. In someembodiments, the pressure is measured upstream of the purge gas lineinlet, within the purge gas line channel or downstream of the purge gasline outlet. A flow of inert gas is provided into the purge channel sothat there is substantially no pressure differential between the gasdistribution plate (or the process pressure) and the purge channel.

Processes may generally be stored in the memory as a software routinethat, when executed by the processor, causes the process chamber toperform processes of the present disclosure. The software routine mayalso be stored and/or executed by a second processor (not shown) that isremotely located from the hardware being controlled by the processor.Some or all of the method of the present disclosure may also beperformed in hardware. As such, the process may be implemented insoftware and executed using a computer system, in hardware as, e.g., anapplication specific integrated circuit or other type of hardwareimplementation, or as a combination of software and hardware. Thesoftware routine, when executed by the processor, transforms the generalpurpose computer into a specific purpose computer (controller) thatcontrols the chamber operation such that the processes are performed.

In some embodiments, the controller 495 has one or more configurationsto execute individual processes or sub-processes to perform the method.The controller 495 can be connected to and configured to operateintermediate components to perform the functions of the methods. Forexample, the controller 495 can be connected to and configured tocontrol one or more of gas valves, actuators, motors, slit valves,vacuum control, etc.

The controller 495 of some embodiments has one or more configurationsselected from: a configuration to measure a pressure in one or more ofthe gas distribution plate 112 channel 130 or the spacer ring purge gaschannel 371; a configuration to actuate a pressure transducer 390 toflow a purge gas into the purge gas line 190 or the spacer ring purgegas line 336; a configuration to control the flow of a purge gas inresponse to a reading from a pressure gauge in one or more of the purgegas outlet line or the channels in the gas distribution plate.

Reference throughout this specification to “one embodiment,” “certainembodiments,” “one or more embodiments” or “an embodiment” means that aparticular feature, structure, material, or characteristic described inconnection with the embodiment is included in at least one embodiment ofthe disclosure. Thus, the appearances of the phrases such as “in one ormore embodiments,” “in certain embodiments,” “in one embodiment” or “inan embodiment” in various places throughout this specification are notnecessarily referring to the same embodiment of the disclosure.Furthermore, the particular features, structures, materials, orcharacteristics may be combined in any suitable manner in one or moreembodiments.

Although the disclosure herein has been described with reference toparticular embodiments, those skilled in the art will understand thatthe embodiments described are merely illustrative of the principles andapplications of the present disclosure. It will be apparent to thoseskilled in the art that various modifications and variations can be madeto the method and apparatus of the present disclosure without departingfrom the spirit and scope of the disclosure. Thus, the presentdisclosure can include modifications and variations that are within thescope of the appended claims and their equivalents.

What is claimed is:
 1. A gas distribution assembly comprising: a gasdistribution plate having a front surface and a back surface defining athickness, the gas distribution plate comprising a plurality ofapertures extending through the thickness of the gas distribution plate,the gas distribution plate having a sealing region at an outer edge, thesealing region having a first contact surface and a second contactsurface, the first contact surface comprising a purge channel formedtherein; a lid having a front surface and a back surface defining athickness, the front surface of the lid positioned adjacent the backsurface of the gas distribution plate, the lid comprising a purge gasline inlet with an opening at the front surface and a purge gas lineoutlet with an opening at the front surface, the inlet opening andoutlet opening aligned with the purge channel of the first contactsurface; and a primary O-ring positioned between the purge channel ofthe first contact surface and the second contact surface.
 2. The gasdistribution assembly of claim 1, wherein the primary O-ring ispositioned in a primary O-ring recess in the first contact surface. 3.The gas distribution assembly of claim 1, further comprising a secondaryO-ring between the back surface of the gas distribution plate and thefront surface of the lid.
 4. The gas distribution assembly of claim 3,wherein the secondary O-ring is on an opposite side of the purge channelfrom the primary O-ring.
 5. The gas distribution assembly of claim 1,wherein the secondary O-ring is in a recess formed in one or more of theback surface of the gas distribution plate or the front surface of thelid.
 6. The gas distribution assembly of claim 1, further comprising apressure transducer in communication with the purge gas line inlet. 7.The gas distribution assembly of claim 6, further comprising a pressuregauge positioned in the purge gas line outlet.
 8. The gas distributionassembly of claim 7, further comprising a controller configured tocontrol the pressure transducer based on measurements from the pressuregauge to provide a flow of inert gas into the purge gas line inletsufficient to maintain substantially no pressure differential betweenthe gas distribution plate and the purge channel.
 9. The gasdistribution assembly of claim 1, further comprising a spacer ringhaving an inside surface and a back surface, the inside surface adjacentan outside surface of the gas distribution plate, the back surfaceadjacent a third contact surface in the sealing region of the gasdistribution plate.
 10. The gas distribution assembly of claim 9,wherein the gas distribution plate further comprises a spacer ring purgegas line extending through the gas distribution plate from the backsurface to the third contact surface, the spacer ring purge gas linecomprising a spacer ring purge gas line inlet with an opening at theback surface of the gas distribution plate and a spacer ring purge gasline outlet with an opening at the back surface of the gas distributionplate, the inlet opening and outlet opening aligned with a spacer ringpurge channel.
 11. The gas distribution assembly of claim 10, whereinthe spacer ring purge channel is formed in one or more of the thirdcontact surface or the back surface of the spacer ring.
 12. The gasdistribution assembly of claim 11, further comprising a pressuretransducer in communication with one or more of the purge gas line inletor the spacer ring gas line inlet.
 13. The gas distribution assembly ofclaim 12, further comprising a pressure gauge positioned in one or moreof the purge gas line outlet or the spacer ring gas line outlet.
 14. Thegas distribution assembly of claim 13, further comprising a controllerconfigured to control the pressure transducer based on measurements fromthe pressure gauge to provide a flow of inert gas into one or more ofthe purge gas line inlet or spacer ring gas line inlet sufficient tomaintain substantially no pressure differential between the gasdistribution plate and the purge channel or between the gas distributionplate and the spacer ring purge channel.
 15. The gas distributionassembly of claim 1, wherein the gas distribution plate comprises aplurality of channels formed in the back surface, each of the pluralityof channels extends a distance toward the front surface to a channelbottom and the apertures are positioned within the channels to extendfrom the channel bottom to the front surface of the gas distributionplate.
 16. A process chamber comprising: a chamber body having sidewallsand bottom bounding a process volume; a substrate support within theprocess volume, the substrate support having a support surface; and agas distribution assembly comprising a gas distribution plate, a lid anda primary O-ring, the gas distribution plate having a front surfacefacing the support surface of the substrate support and a back surfacedefining a thickness, the gas distribution plate comprising a pluralityof apertures extending through the thickness of the gas distributionplate, the gas distribution plate having a sealing region at an outeredge, the sealing region having a first contact surface and a secondcontact surface, the first contact surface comprising a purge channelformed therein, the lid having a front surface and a back surfacedefining a thickness, the front surface of the lid positioned adjacentthe back surface of the gas distribution plate, the lid comprising apurge gas line inlet with an opening at the front surface and a purgegas line outlet with an opening at the front surface, the inlet openingand outlet opening aligned with the purge channel of the first contactsurface, and the primary O-ring positioned between the purge channel ofthe first contact surface and the second contact surface.
 17. Theprocess chamber of claim 16, wherein the gas distribution assemblyfurther comprises a spacer ring having an inside surface and a backsurface, the inside surface adjacent an outside surface of the gasdistribution plate, the back surface adjacent a third contact surface inthe sealing region of the gas distribution plate.
 18. The gasdistribution assembly of claim 17, wherein the gas distribution platefurther comprises a spacer ring purge gas line extending through the gasdistribution plate from the back surface to the third contact surface,the spacer ring purge gas line comprising a spacer ring purge gas lineinlet with an opening at the back surface of the gas distribution plateand a spacer ring purge gas line outlet with an opening at the backsurface of the gas distribution plate, the inlet opening and outletopening aligned with a spacer ring purge channel.
 19. The gasdistribution assembly of claim 18, further comprising a pressuretransducer in communication with one or more of the purge gas line inletor the spacer ring gas line inlet, a pressure gauge positioned in one ormore of the purge gas line outlet or the spacer ring gas line outlet,and a controller, the controller configured to control the pressuretransducer based on measurements from the pressure gauge to provide aflow of inert gas into one or more of the purge gas line inlet or spacerring gas line inlet sufficient to maintain substantially no pressuredifferential between the gas distribution plate and the purge channel orbetween the gas distribution plate and the spacer ring purge channel.20. A method of sealing a process chamber, the method comprising:measuring a pressure in a purge gas line downstream of a purge gas lineoutlet aligned with a purge channel in a gas distribution assemblycomprising a gas distribution plate and a lid separated by a primaryO-ring, the purge gas line in fluid communication with a purge channeland a purge gas line inlet, each of the purge gas line inlet and purgegas line outlet aligned with the purge channel; and providing a flow ofinert gas into the purge channel so that there is substantially nopressure differential between the gas distribution plate and the purgechannel.